A 0.05-kg car starts from rest at a height of 0.95 m. Assuming no friction, what is the kinetic energy of the car when it reache

Question

2 years ago

7

s the bottom of the hill? (Assume g = 9.81 m/s2.)
A. 0.466 J
B. 0.308 J
C. 4.317 J
D. 0.0475 J

2 answers:

aleksandr82 [10.1K] · Answer 1 · 2022-08-10T12:25:49+03:00

The kinetic energy of the car when it reaches the bottom of the hill is about A. 0.466 J

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<h3>Further explanation</h3>

<em>Let's recall </em><em>Kinetic Energy</em><em> Formula as follows:</em>

$\large {\boxed{Ek = \frac{1}{2}mv^2} }$

Ek = Kinetic Energy ( Joule )

m = mass of the object ( kg )

v = speed of the object ( m/s )

Let us now tackle the problem !

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<u>Given:</u>

mass of the car = m = 0.05 kg

initial speed of toy car = u = 0 m/s

initial height position of the car = h₁ = 0.95 m

final height position of the car = h₂ = 0 m

gravitational acceleration = g = 9.81 m/s²

<u>Asked:</u>

final kinetic energy of the car = Ek₂ = ?

<u>Solution:</u>

<em>We will use </em><em>Conservation of Energy</em><em> to solve this problem:</em>

$Ep_1 + Ek_1 = Ep_2 + Ek_2$

$mgh_1 + \frac{1}{2} m u^2 = mgh_2 + Ek_2$

$mgh_1 + \frac{1}{2} m (0)^2 = mg(0) + Ek_2$

$mgh_1 = Ek_2$

$Ek_2 = 0.05 \times 9.81 \times 0.95$

$Ek_2 \approx 0.466 \texttt{ J}$

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<h3>Learn more</h3>

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<h3>Answer details</h3>

Grade: High School

Subject: Physics

Chapter: Energy

statuscvo [17] · Answer 2 · 2022-08-10T10:29:55+03:00

6 0

The kinetic energy of the car is A.) 0.466 J